Question

Solve the system of equations by first multiplying 2x + y = 1 3x + 3y = 15 Write the solution as an ordered pair:_____

Answer 1

Multiply the equation 2x + y = 1 by 3 to obtain same coefficients of y.

`\begin{gathered} (2x+y=1)*3 \\ 3\cdot2x+3\cdot y=3\cdot1 \\ 6x+3y=3 \end{gathered}`

Substract the equation 3x + 3y = 15 from 6x + 3y = 3 to eliminate the terms of y.

`\begin{gathered} 6x+3y-(3x+3y)=3-15 \\ 3x=-12 \\ x=-(12)/(3) \\ =-4 \end{gathered}`

Substitute -4 for x in the equation 2x + y = 1 to obtain the value of y.

`\begin{gathered} 2\cdot(-4)+y=1 \\ -8+y=1 \\ y=1+8 \\ =9 \end{gathered}`

So solution of equations is (-4,9).